1.3 Theories of Human Development

As you read earlier in this chapter, the scientific method begins with observations, questions, and theories (step 1). These lead to specific hypotheses that can be tested (step 2). A theory is a comprehensive and organized explanation of many phenomena; a hypothesis is more limited and may be proven false. Theories are generalities; hypotheses are specific. Data are collected through research (step 3), conclusions are drawn (step 4), and the results are reported (step 5) and replicated.

Although developmental scientists are intrigued by all their observations, theories are crucial to start the scientific process. Theories sharpen their perceptions and organize the thousands of behaviours they observe every day. Every developmental theory is a systematic statement of principles and generalizations, providing a framework for understanding how and why people change over the life span. We need theories to “help us describe and explain developmental changes by organizing and giving meaning to facts and by guiding future research” (P. H. Miller, 2011). Theories connect facts with patterns, weaving the details of life into a meaningful whole.

You will encounter dozens of theories throughout this text, each one useful in organizing data and developing hypotheses. Six major theories that apply to the entire life span are introduced here; more details about each of them appear later in this text.

Psychoanalytic Theory

Freud at Work In addition to being the world’s first psychoanalyst, Sigmund Freud was a prolific writer. His many papers and case histories, primarily descriptions of his patients’ bizarre symptoms and unconscious sexual urges, helped make the psychoanalytic perspective a dominant force for much of the twentieth century.

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Inner drives and motives are the foundation of psychoanalytic theory. These basic underlying forces are thought to influence every aspect of thinking and behaviour, from the smallest details of daily life to the crucial choices of a lifetime (Dijksterhuis & Nordgren, 2006). Psychoanalytic theory is often treated as a stage theory because it sees each child going through distinct and sequential levels or stages. Each stage in a child’s development builds upon the last and prepares for the next. For example, in developing math skills, children need to learn what numbers are before they can add. Once they can add, the next step is subtraction, then multiplication, and then division. Skipping or failing to master one stage will lead to problems in the next. Many psychoanalytic theorists believe that human development proceeds in just such a fashion, in clearly defined and complementary stages.

Freud’s StagesPsychoanalytic theory originated with Sigmund Freud (1856–1939), an Austrian physician who treated patients suffering from mental illness. He listened to their dreams and fantasies and constructed an elaborate, multi-faceted theory.

According to Freud, development in the first six years occurs in three stages, each characterized by sexual pleasure centred on a particular part of the body. Infants experience the oral stage, so named because the erotic body part is the mouth, followed by the anal stage in early childhood, with the focus on the anus. In the preschool years (the phallic stage), the penis becomes a source of pride and fear for boys and a reason for sadness and envy for girls.

In middle childhood comes latency, a quiet period that ends when one enters the genital stage at puberty. Freud was the most famous theorist who thought that development stopped after puberty and that the genital stage continued throughout adulthood (see TABLE 1.3).

Spiked Hair and Piercings This adolescent thinks that she is a nonconformist; her spiked red hair and multiple tattoos and piercings are certainly unlike those of her mother or grandmother. But she is similar to adolescents everywhere—seeking to establish their own distinct identity.

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Freud maintained that at each stage, sensual satisfaction (from stimulation of the mouth, anus, or genitals) is linked to developmental needs, challenges, and conflicts. How people experience and resolve these conflicts—especially those related to weaning (oral), toilet training (anal), male roles (phallic), and sexual pleasure (genital)—determines their personality patterns, because “the early stages provide the foundation for adult behavior” (Salkind, 2004). For example, Freud believed that the gratification of needs helped children develop a sense of independence.

Erikson’s StagesMany of Freud’s followers became famous theorists themselves. The most notable in human development was Erik Erikson (1902–1994), who described eight developmental stages, extending Freud’s five-stage theory to old age. Perhaps this extension was influenced by his own adult life, when he made several dramatic moves. He was a wandering artist in Italy, a teacher in Austria, and a Harvard professor in the United States.

Erikson named two polarities at each stage (which is why the word versus is used in each), but he recognized that many outcomes between these opposites are possible (Erikson, 1963). For most people, development at each stage leads to neither extreme. For instance, the generativity-versus-stagnation stage of adulthood rarely involves a person who is totally stagnant—no children, no work, no creativity. Instead, most adults are somewhat stagnant and somewhat generative.

Like Freud, Erikson believed that adults’ problems echo their childhood conflicts. For example, an adult who cannot form a secure, close relationship with someone else (intimacy versus isolation) may not have resolved the crisis of infancy (trust versus mistrust). However, Erikson’s stages differ significantly from Freud’s in that, first, Erikson’s theory was a life-span theory with a specific crisis at each stage of life, from infancy to old age. Second, Erikson emphasized the importance of family and culture, not sexual urges. He called his theory epigenetic, partly to stress that the social environment strongly influences genes and biological impulses.

Before psychoanalytic theory, most scientists ignored the first years of life. Both Freud and Erikson noted that psychological conflicts—especially in childhood within families—affect people throughout their lives, an insight that developmentalists now accept.

A Legendary Couple In his first 30 years, Erikson frequently changed nations, schools, and professions. Then he met Joan. In their first five decades of marriage, they raised a family and wrote several books. If he had published his theory at age 73 (when this photograph was taken) instead of in his 40s, would he still have described his life as a series of crises?

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Learning Theory

From the beginning, psychoanalytic theory was criticized by scientists who said it was difficult to measure internal motives and drives, especially those stemming from the unconscious mind. Out of this criticism came learning theory, which focuses on overt behaviours that can be directly observed. Learning theory argues that behaviour is influenced by the social environment and by how people are rewarded or punished when they act in certain ways. Two important learning theories are behaviourism and social learning theory.

BehaviourismBehaviourism arose in direct opposition to the psychoanalytic emphasis on unconscious, hidden urges (differences are described in TABLE 1.4). Early in the twentieth century, John B. Watson (1878–1958) argued that scientists should examine only what they could observe and measure. According to Watson, if psychologists focus on behaviour, they will realize that anything can be learned. Watson wrote:

An Early Behaviourist John Watson was an early proponent of learning theory. His ideas are still influential and controversial today.

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Many other psychologists, especially in the United States, agreed. They found that the unconscious motives and drives that Freud described were difficult (or impossible) to verify via the scientific method (Uttal, 2000). For instance, researchers found that, contrary to Freud’s view, parents’ approach to toilet training did not determine a child’s later personality. Thus, behavioural psychologists believed that what children learn, especially in regard to social behaviour, is acquired from their environment.

For every individual at every age, from newborn to centenarian, behaviourists have identified laws to describe how environmental responses shape what people do. All behaviour, from reading a book to robbing a bank, follows these laws. Every action is learned, step by step. As the saying goes, “monkey see, monkey do.”

ConditioningThe specific laws of learning apply to conditioning, the processes by which responses become linked to particular stimuli. There are two types of conditioning: classical and operant.

More than a century ago, Ivan Pavlov (1849–1936), a Russian scientist who won a Nobel Prize for his work on animal digestion, noticed that his experimental dogs drooled not only when they saw and smelled food but also when they heard the footsteps of the attendants who brought the food. This observation led Pavlov to perform experiments in which he conditioned dogs to salivate when they heard a specific sound.

A Contemporary of Freud Ivan Pavlov was a physiologist who received the Nobel Prize in 1904 for his research on digestive processes. It was this line of study that led to his discovery of classical conditioning.

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Pavlov began by ringing a bell just before presenting food to the dogs. After a number of repetitions of the ringing-then-food sequence, the dogs began salivating at the sound, even when no food was present. This simple experiment demonstrated classical conditioning (sometimes called respondent conditioning), a process in which, over time, a person or animal learns to associate a neutral stimulus (the sound) with a meaningful stimulus (the food) to elicit a response (salivation).

The most influential North American behaviourist was B. F. Skinner (1904–1990). He agreed with Watson that psychology should focus on the scientific study of behaviour, and that classical conditioning explains some behaviour. However, Skinner stressed another type of conditioning, operant conditioning (sometimes called instrumental conditioning). In operant conditioning, animals perform some action and then a response occurs. If the response is useful or pleasurable, the animal is likely to repeat the action. If the response is painful, the animal is not likely to repeat the action. In both cases, the animal has learned. Pleasant consequences are sometimes called rewards, and unpleasant consequences are sometimes called punishments. Behaviourists hesitate to use those words, however, because what people commonly think of as a punishment can actually be a reward, and vice versa. For example, parents punish their children by withholding dessert, by giving them a time out, by not letting them play, by speaking harshly to them, and so on. But if a particular child dislikes the dessert, being deprived of it is actually a reward, not a punishment. Another child might not mind a time out, especially if he or she craves quiet time. For that child, the intended punishment (a time out) is actually a reward (quiet).

Rats, Pigeons, and People B. F. Skinner is best known for his experiments with rats and pigeons, but he also applied his knowledge to human problems. For his daughter (shown here), he designed a glass-enclosed crib in which temperature, humidity, and perceptual stimulation could be controlled to make her time in the crib enjoyable and educational.

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Any consequence that follows a behaviour and makes the person (or animal) likely to repeat that behaviour is called a positive reinforcement, not a reward. Once a behaviour has been conditioned, humans and other creatures will repeat it even if reinforcement occurs only occasionally. Similarly, an unpleasant response makes a creature less likely to repeat a certain action.

This insight has practical application. Early responses are crucial for development because children learn habits that endure. For example, when I was a child, my father would come home, announce his arrival, and hope to be greeted by his four children, to no avail. So at one point, he started yelling out, “Chocolate bars!” whenever he arrived home, and we all came running to pull the treats from his pockets. After a while, the chocolate bars stopped, but by then we had developed the habit of giving our father a warm welcome at the end of the day. In this way, my father reinforced family solidarity.

The science of human development has benefitted from behaviourism. The theory’s emphasis on the origins and consequences of observed behaviour led to the realization that many actions that seem to be genetic, or to result from deeply rooted emotional problems, are actually learned. And if something is learned, it can be unlearned. No longer are “the events of infancy and early childhood…the foundation for adult personality and psychopathology,” as psychoanalysts believed (Cairns & Cairns, 2006). People can change; plasticity continues throughout one’s life.

Still Social Even in his 80s, Albert Bandura is on the faculty at Stanford University, where he is continuing his research on the effects of modelling on behaviour, feelings, and thought patterns.

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Social Learning TheoryA major extension of behaviourism is social learning theory, which was first described by Albert Bandura (b. 1925), who was born and raised in Alberta. He is currently a professor emeritus at Stanford University. Social learning theory notes that, because humans are social beings, they learn from observing others, even without personally receiving any reinforcement.

This form of learning theory is often called modelling because people learn by observing role models. For example, researchers have found that children who witness domestic violence are influenced by it. As the multicontextual approach would predict, what they learn varies. In a family in which the father often hits the mother, one son might identify with the abuser and another with the victim. Later in adulthood, because of their past social learning, one man might slap his wife and spank his children, while his brother might be fearful and apologetic at home. They learned opposite lessons. Differential sensitivity may also be evident: a third sibling may not be affected in adulthood by past memories of domestic violence.

Cognitive Theory

Listen and Learn Jean Piaget called himself a “genetic epistemologist”—one who studies how children gain knowledge about the world as they grow up. He learned about children by listening carefully to them as they spoke—especially to their incorrect explanations, which no one had paid much attention to before.

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In a third type of theory, each person’s ideas and beliefs are of central importance. According to cognitive theory, thoughts and expectations profoundly affect actions. Cognitive theory has dominated psychology since about 1980 and has branched into many versions, each adding insights about human development. The word cognitive refers not just to thinking but also to attitudes, beliefs, and assumptions.

The most famous cognitive theorist was a Swiss scientist, Jean Piaget (1896–1980). Unlike other scientists of the early twentieth century, Piaget realized that babies are themselves like “little scientists.” They are curious and thoughtful, creating their own interpretations about their world. Piaget began by observing his own three infants; later he studied thousands of older children (Inhelder & Piaget, 1958).

From this work, Piaget developed the central theme of cognitive theory: How people think (not just what they know) changes with time and experience, and human thinking influences human actions. Piaget maintained that cognitive development occurs in four major age-related periods, or stages: sensorimotor, preoperational, concrete operational, and formal operational (see TABLE 1.5).

FIGURE 1.10 Challenge Me Most of us, most of the time, prefer the comfort of our conventional conclusions. According to Piaget, however, when new ideas disturb our thinking, we have an opportunity to expand our cognition with a broader and deeper understanding.

Intellectual advancement occurs throughout one’s life because humans seek cognitive equilibrium—that is, a state of mental balance. An easy way to achieve this balance is to interpret new experiences through the lens of pre-existing ideas. For example, infants discover that new objects can be grasped in the same way as familiar objects; older adults speak fondly of the good old days as embodying values that should endure.

Sometimes, however, a new experience is jarring and incomprehensible. The resulting experience is one of cognitive disequilibrium, an imbalance that initially creates confusion. As Figure 1.10 illustrates, disequilibrium leads to cognitive growth because it forces people to adapt their old concepts. Piaget describes two types of adaptation:

• Assimilation, in which new experiences are interpreted to fit into, or assimilate with, old ideas
• Accommodation, in which old ideas are restructured to include, or accommodate, new experiences.

Accommodation requires more mental energy than assimilation, but it is sometimes necessary because new ideas and experiences may not fit into existing cognitive structures. Accommodation produces significant intellectual growth. For example, think of cognitive structures as filing cabinets. A child has a family cat that is black and white. Learning that this animal is called a “cat,” the child creates a “cat folder.” When the child meets a brown cat, she has no trouble learning that in spite of its difference in colour, it is also a “cat” and can be filed away into the “cat folder.”This new information becomes assimilated (added) in the “cat folder.” Now, when the child meets a dog, she may at first think that it’s a cat, since it also has four legs and a long tail. However, her parents tell her that this new animal is actually a dog! She now needs to make a “dog folder” to accommodate this new information.

Another influential cognitive theory, called information processing, differs from Piaget’s theory. Information-processing theory (which is discussed in Chapter 3) describes the steps of cognition with details, not stages, and with attention to perceptual and neurological processes. Many researchers (in addition to those influenced by information-processing theory) now think that some of Piaget’s conclusions were mistaken. However, every developmentalist appreciates Piaget’s basic insight: Thoughts can influence emotions and actions.

Like Father, Like Son It’s not difficult to figure out where this boy got the idea to show off his biceps!

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Systems Theory

Many useful twenty-first-century developmental theories describe systems that involve the interaction of various forces and people. The word systems captures the idea that a change in one part of a person, family, or society affects every aspect of development because each part is connected to all the other parts (Spencer et al., 2006).

Human development depends on systems. Consider examples from the three domains of development. Some systems are physiological, such as the immune system, which includes many kinds of immune cells. Some systems are cognitive, such as language, with sounds, words, and grammar all working together to produce communication. And some are social, such as the members of a family, workers in a factory, or citizens of a town. Minor dysfunctions can be overcome, but a major dysfunction can bring the whole system to a dead stop.

We have already considered one important systems theory earlier in this chapter, Urie Bronfenbrenner’s ecological-systems approach. Here we will examine another and more recent way of understanding human development called family systems theory.

Family Systems TheoryAs Bronfenbrenner focused on various microsystems to help explain development, family systems theory focuses on the family as a unit or functioning system with its own set of rules that keep it operating over time. Systems theory is useful in understanding the complex interactions among family members, including the way they make decisions, set and achieve certain goals, and create rules to regulate behaviours. Much of family systems theory developed from the work and writings of the renowned therapist Salvador Minuchin (b. 1921) in the 1970s.

How to Think About Flowers A person’s stage of cognitive growth influences how he or she thinks about everything, including flowers. (a) At the preoperational stage, flowers fit into the egocentric scheme. Claire, a young girl from British Columbia, wants to touch, smell, and pick the flowers, not realizing how others might perceive such actions. (b) At the adult’s formal operational stage, flowers can be part of a larger, logical scheme—either to earn money or to cultivate beauty. Thinking is an active process from the beginning of life until the end.

EMILIE GLADSTONE
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According to Minuchin (1974), it is impossible to understand how families operate without considering the concept of wholeness. Each family member makes up a part of the whole, and each member is connected with every other member. This interdependence of family members means that what affects one has an effect on every other member and on the family as a whole.

Think of a time in your own family history when something significant happened. Perhaps your grandfather died, your mother got a promotion that meant moving to another city, or your parents divorced. Whether for good or bad, the whole family has to react in such a situation, and every reaction results in some kind of change. Whenever this happens, the family system makes an effort to stabilize itself, to return to a state of balance or what theorists call homeostasis.

The way family members influence each other in a back-and-forth fashion is called reciprocal interaction and feedback. When one member behaves in a certain way, this calls forth a reaction (or reciprocal interaction) from another. However, this interplay of cause and effect does not end there. Feedback also occurs, a type of reaction that sparks yet another response and keeps the exchange going. For example, a baby may smile at her mother, causing the mother to smile back and move closer. At this, the baby provides feedback by laughing, and the mother starts tickling the baby to make her laugh again.

Over time, patterns emerge in every family whereby behaviours become regulated, allowing each member to anticipate other members’ actions. Three factors are responsible for regulating behaviours: rules, roles, and communication styles.

Parents or guardians usually decide what the rules will be, providing a common understanding for acceptable and unacceptable behaviours. Rules can either be explicit, as when parents tell teens exactly what their curfew is, or implicit, as when it is simply understood that children will enhance their career prospects by going to university or college.

Each person assumes a specific role in the family (as mother, father, son, or daughter), and with a role comes a set of expected behaviours and responsibilities. For instance, a 15-year-old son’s role might involve being a good student, keeping a clean room, and doing some of the household chores.

Communication styles are important in determining the quality of family relationships. There are three types of communication styles: verbal, nonverbal, and contextual. Verbal communications consist of the words spoken out loud among family members. These words are usually accompanied by some type of nonverbal communication such as bodily gestures and facial expressions. Both verbal and nonverbal communications are delivered within a specific context that usually enhances the message in some way. For example, when parents force a child to say “sorry,” this is a very different context from when a child spontaneously and willingly offers an apology (Beevar & Beevar, 1998).

As families develop their own unique sets of patterns, they also create certain boundaries that are useful in setting limits for acceptable behaviours. Boundaries can either strengthen or weaken the health of a family system. Families that are open systems have boundaries that are flexible, and they are willing to exchange information and interactions with other families and individual people. In contrast, closed systems set inflexible boundaries and are unwilling to accept outside information and interactions. For example, many families refuse to discuss mental health issues or to seek therapy for a family member until the illness has escalated to a dangerous level.

Humanism

Many scientists are convinced that there is something hopeful, unifying, and noble in the human spirit, something ignored by psychoanalytic theory and behaviourism. The limits of those two major theories were especially apparent to Abraham Maslow (1908–1970), one of the founders of humanism. Maslow believed that all people—no matter what their culture, gender, or background—have the same basic needs and drives. He arranged these needs in a hierarchy (see Figure 1.11):

1. Physiological: needing food, water, warmth, and air
2. Safety: feeling protected from injury and death
3. Love and belonging: having loving friends, family, and a community
4. Esteem: being respected by the wider community as well as by oneself
5. Self-actualization: becoming truly oneself, fulfilling one’s unique potential.

FIGURE 1.11 Moving Up, Not Looking Back Maslow’s hierarchy is like a ladder: Once a person stands firmly on a higher rung, the lower rungs are no longer needed. Thus, someone who has arrived at step 4 might devalue safety (step 2) and be willing to risk personal safety to gain respect.

At self-actualization, when basic needs have been met, people can be fully them-selves—creative, spiritual, curious, appreciative of nature, and able to respect everyone else. The person has “peak experiences” when life is so intensely joyful that time stops and self-seeking disappears.

Maslow contended that everyone must satisfy each lower level before moving higher. A starving man, for instance, may risk his life to secure food (level 1 precedes level 2), or an unloved woman might not care about self-respect because she needs affection (level 3 precedes level 4). People may be destructive and inhumane, not self-actualizing, because of unmet lower needs.

Although humanism does not postulate stages, a developmental application of this theory is that satisfying childhood needs is crucial for later self-acceptance. Thus, when babies cry in hunger, that basic need should be met. People may become thieves or even killers, unable to reach their potential, if they were unsafe or unloved as children.

This theory is prominent among medical professionals because they realize that pain can be physical (the first two levels) or social (the next two) (Majercsik, 2005; Zalenski & Raspa, 2006). Even the very sick need love and belonging (family should be with them) and esteem (the dying need respect).

Evolutionary Theory

Charles Darwin’s basic ideas about evolution were first published 150 years ago (Darwin, 1859), but serious research on human development inspired by evolutionary theory is quite recent (Gangestad & Simpson, 2007).

According to this theory, nature works to ensure that each species does two things: survive and reproduce. Consequently, many human impulses, needs, and behaviours evolved to help humans survive and thrive over 100 000 years (Konner, 2010). Evolutionary theory has intriguing explanations for many phenomena in human development, including women’s nausea in pregnancy, 1-year-olds’ attachment to their parents, puberty in young adolescents, emerging adults’ sexual preferences, parents’ investment in their children, and the increase in neurocognitive disorder, cancer, and other diseases in late adulthood.

To understand human development, this theory contends, humans need to recognize what was adaptive thousands of years ago. For example, it is irrational that many people are terrified of snakes (which cause 1 death in a billion), but virtually no one fears automobiles (which cause about 1 death in 5000). Evolutionary theory suggests that the fear instinct evolved to protect life when snakes killed many people, which was true until quite recent history. Our fears have not caught up to modern life.

Some of the best human qualities, such as cooperation, spirituality, and self-sacrifice, may have also originated thousands of years ago when groups of people survived because they took care of one another. Childhood itself, particularly the long period when children depend on others while their brains grow, can be explained via evolution (Konner, 2010). So can the fact that, unlike chimpanzees, human mothers prefer fathers to be involved in their children’s lives, and they accept assistance from other relatives and even strangers. Shared child care allows women to have children every two years or so, unlike chimpanzees who wait at least four years between births (Hrdy, 2009).